1. Technical Field
The present invention relates to a fluoropolymer composition.
2. Background
Fluoropolymers are used as various types of sealing members such as packing, gaskets, O-rings, and the like in the automotive market, industrial market, and electric and electronic market, because of the excellent heat resistance, oil resistance, weather resistance, low fuel permeability, and high compression permanent strain resistance thereof. However, there are frequently problems with sticking or adhering to substrates such as metal, plastic, rubber, ceramic, and the like. In other words, if a fluoropolymer member is in contact with these substrates for a long period of time, there is a problem that this may cause the fluoropolymer to stick or adhere.
For example, there is a possibility that, through sticking or adhering, a sealing member used in a semiconductor manufacturing process can contaminate the semiconductor component because of minute fragments (powder) that occur or can cause damage to the equipment because of breaking or detaching of old seal material fragments that have been degraded, when replacing with new components. Furthermore, with sealing members (such as electromagnetic valves) that are frequently opened and closed, equipment may stop operating properly because of sticking or adhering, possibly inducing failure when opening and closing.
With a stopper for a hard disk drive, there are problems with a malfunction similarly caused by sticking between the stopper and an arm. For example, the arm will not function properly because of sticking and adhering, and there will be problems with either reading or writing data to the hard disk drive or the like. Therefore, in many applications where there is contact between seals and other substrates, in addition to excellent sealing properties, there is strong demand for low tackiness or non-tackiness (also referred to as “low/non tackiness” in the present invention) and low adhesion or non-adhesion (also referred to as “low/non adhesion” in the present invention), with regard to the substrate. Many methods have been proposed in order to achieve low or non-tackiness and low or non-adhesion.
Conventionally, the addition of oils (for example silicone oil) is commonly known as a method for reducing sticking and adhering to various types of substrates. However, the additional oil causes inferior physical properties, and oil that leaks to the surface is tacky, and may be a cause of contamination on the rubber surface in some cases. Furthermore, the additional oils may cause malfunction or improper function of electronic devices such as a hard disk drive or the like due to gases produced and denatured deposits thereof.
Japanese Unexamined Patent Application Publication No. S63-291930 (Patent Document 1) discloses a method of modifying a fluorine containing elastomer molded article wherein the surface of a vulcanized molded part of a fluorine containing elastomer is subject to secondary vulcanization in the presence of a polyhydroxy compound. Japanese Unexamined Patent Application Publication No. H01-131255 (Patent Document 2) discloses a surface modified elastomer vulcanized molded body made by crosslinking with a vulcanizing agent, and then crosslinking toward the inner part from the surface of the molded body by using the crosslinking agent that has permeated from the surface. Japanese Unexamined Patent Application Publication No. H10-87863 (Patent Document 3) discloses a surface treatment solution for a fluorine rubber vulcanized material containing a crosslinking agent, alkali, and onium salt in a solvent, wherein the crosslinking agent is a dithiol compound. Japanese Unexamined Patent Application Publication No. S61-81437 (Patent Document 4) discloses a surface treatment method for a vulcanized fluorine rubber molded article wherein the surface of a vulcanized fluorine rubber molded article is treated with an amine or amine salt. Japanese Unexamined Patent Application Publication No. H1-190447 (Patent Document 5) discloses a non-tacky treatment method for surface treating a fluorine rubber vulcanized material containing a predetermined amount of bisamidate or alkylurea compound using an amine or amine salt.
Japanese Unexamined Patent Application Publication No. S59-71336 (Patent Document 6) discloses a surface treatment method for a molded rubber material, wherein the surface of the molded rubber material is treated with nitrogen plasma. Japanese Unexamined Patent Application Publication No. 2003-286357 (Patent Document 7) discloses a non-tackifying treatment method for a fluorine rubber molded body wherein nonequilibrium plasma of a saturated fluorocarbon gas is irradiated onto a cross-linked or non-cross-linked molded body made of fluorine rubber or a fluorine rubber composition. Japanese Unexamined Patent Application Publication No. 2005-82654 (Patent Document 8) discloses a non-tackifying method for a fluorine rubber molded body, wherein a fluorine rubber molded body is irradiated with a nonequilibrium plasma having a predetermined pressure and containing an olefin fluoride or containing an alkane fluoride where a ratio of a number of fluorine atoms to a number of carbon atoms is 2 or less.
Japanese Unexamined Patent Application Publication No. H01-141909 (Patent Document 9) discloses a surface treatment agent for a polymer containing a predetermined amount of a silicon functional silyl isocyanate and a predetermined amount of a hardening polyester. Japanese Unexamined Patent Application Publication No. H01-301725 (Patent Document 10) discloses a non-tacky fluorine rubber composition wherein a fluorine rubber-silicone reaction layer is formed on a vulcanized fluorine rubber surface.
Japanese Unexamined Patent Application Publication No. 2005-206627 (Patent Document 11) discloses a metal non-adhesive perfluoroelastomer molded body wherein a perfluoroelastomer cross-linked molded body is coated with an amorphous fluorine resin.
Japanese Unexamined Patent Application Publication No. H2-261850 (Patent Document 12) discloses a method where a predetermined amount of fluorine resin powder, a predetermined amount of organic solvent, and a vulcanizing agent are blended into a fluorine rubber, and then the fluorine rubber blend is heat treated and then molded.
Japanese Unexamined Patent Application Publication No. H01-60640 (Patent Document 13) discloses a non-tacky fluorine rubber composition where a predetermined bisamidate or alkyl urea compound is added to a fluorine rubber.
Japanese Unexamined Patent Application Publication No. 2006-143977 (Patent Document 14) proposes a fluorine rubber composition where a predetermined amount of barium stearate is added to a polyol vulcanized fluorine rubber.
Japanese Unexamined Patent Application Publication No. H06-16892 (Patent Document 15) discloses a method for manufacturing a low tackiness fluorine rubber, wherein a predetermined amount of an anti-aging agent with an antioxidant effect is added to a fluorine rubber blend, and then vulcanized and molded.
Japanese Unexamined Patent Application Publication No. 2007-284608 (Patent Document 16) discloses a non-tacky low friction fluorine rubber composition, wherein a predetermined amount of zinc oxide and magnesium oxide are added as an acid acceptor to a ternary fluorine rubber.
Japanese Unexamined Patent Application Publication No. 2011-12212 (Patent Document 17) discloses a manufacturing method for a fluorine rubber molded article, including (I) a kneading step of obtaining a crosslinking fluorine rubber composition by kneading (A) a fluorine rubber containing a tetrafluoroethylene/propylene copolymer and (B) a fluorine resin, at or above the melting point of the fluorine resin (B), (II) a molding and crosslinking step of obtaining a cross-linked molded article by molding the crosslinking fluorine rubber composition and then crosslinking, and (III) a heat treatment step of obtaining a fluorine rubber molded article by heat treating the cross-linked molded article at a temperature at or above the melting point of the fluorine resin (B).